1. Field of the Invention
The present invention relates to a safety device designed to lower the reactivity of a nuclear reactor by the extremely rapid introduction of a liquid absorbant into a space located in the core of the reactor.
2. Prior Art
The devices for arresting a reactor by introducing a liquid absorbent have the advantage over the conventional devices such as control rods in that they are able to function even in the event of an explosion or a serious accident in the reactor.
Certain of the known liquid absorbent arresting devices operate by injecting the absorbent directly into the liquid refrigerant or into the moderator. It is then very difficult to extract the absorbent from the moderator and absorbent separation devices are very cumbersome and costly.
In the case of other known devices, the absorbent circulates in the pipes crossing right through the reactor. The absorbent is kept ready without the core of the reactor by means of gas pressure and the supply of absorbent is stored outside the reactor in a drum governed by gas pressure. All that is required to force the absorbent into the pipes crossing the core of the reactor is to rapidly increase the gas pressure in the drum or to reduce the pressure keeping the absorbent out of the core of the reactor.
These devices have the disadvantage of requiring external manipulation to set them into operation. Furthermore, the liquid-filled pipes are relatively long which produces charging losses and sluggishness of the flow of liquid. This prejudices a rapid response and calls for very high pressures. In addition, this sluggishness has a detrimental effect at the end of the flow course thus necessitating the use of damping devices to check the flow of liquid.